You will snap those servos and plant a balsa tree.. I broke an HS-635 on an aileron 2nd flight.. I use HS-625's and they are the best non-digital servo for the plane.. Chris will not stand behind you unless you use metal gears.. A YS-140 is overkill but I guess if you have one lying around you could use it.. If not go with Clam's recommendation.. 90% of us use YS 1.10's with it.. If I had to do it all over again I would use a small RCS 140 gasser as I am getting out of glow engines..